At the GRUB screen select the entry you wish to boot in to (most likely the one that's selected as default), press e and then remove 'quiet' and 'splash' from the kernel line if present. You can then press Ctrl-X to boot. This might display a little more information that could be useful. Edit: tumbleweed's suggestion is better, try rescue mode
–
benwhJan 5 '12 at 7:56

It doesn't boot in rescue mode. It is stuck at the same error. I'm wondering how to copy/paste all the information from the rescue screen.
–
Ivan DokovJan 5 '12 at 8:16

1

Could you grab /var/log/kern.log from your Ubuntu partition using a Live CD?
–
LekensteynJan 5 '12 at 10:05

On sda6 I have the Ubuntu OS. It is the right partition. I've booted from a LiveCD and I see the /sbin/init file in /dev/sda6. I actually don't know how to fix the /sbin/init, but I don't want to reinstall the OS for sure. Help me out fixing the init. PS: Before I post the topic here I did partition check with Gparted from Live CD. It didn't helped.
–
Ivan DokovJan 5 '12 at 9:16

It seems I will reinstall the OS after all.
–
Ivan DokovJan 5 '12 at 10:01

1

I hate to have to suggest that, I'm sure it's fixable, but hard to say how, without sitting down and playnig with the machine...
–
tumbleweedJan 5 '12 at 10:04

I had a lot of trouble with that same exact problem and it took me a while but i managed to fix my problem with the following solution.
I installed Boot repair and repaired my file system. I have LVM(logical volume mangement) and i couldnt run fsck. you can follow how to install it from https://help.ubuntu.com/community/Boot-Repair
or